312 THE CIRCULATORY SYSTEM. 
sends several branches dorsad (toward the knee), and at about 
the middle of the lower leg it divides into two main branches, 
a dorsal branch (£), passing to the dorsum of the foot, anda 
plantar branch (7), to the sole of the foot. The dorsal branch 
is accompanied by the main saphenous nerve (g) and vein. It 
sends one or two branches to the medial side of the ankle- 
joint, passes then onto the dorsum of the foot, and divides into 
four main branches. The medial one passes along the medial 
side of the medial digit; the other three pass to the intervals 
between the digits. Each divides into two branches which 
supply the contiguous sides of the two digits between which 
the interval lies. The dorsal branch thus supplies arteries to 
the sides of all the digits except to the lateral side of the lateral 
digit. This is supplied by A. suralis. 
The plantar branch (7) is larger than the dorsal. It passes 
distad on the medial surface of the flexor longus hallucis, ’ 
accompanied by the tibial nerve, and across the space between 
the tendon of Achilles and the flexor. It gives superficial and 
deep branches to the structures about the ankle-joint, and 
sends inward a branch from the lateral side (Fig. 128, @) 
which joins the termination of A. tibialis anterior to form the 
plantar arch. It then passes distad along the plantar surface 
of the foot, nearer its medial border. Beneath the pad in the 
sole of the foot it divides into three branches which supply the 
interosseous spaces between the three digits. 
e. A. poplitea.—The main trunk of the femoral artery 
passes between the vastus medialis and the semimembranosus 
and then through the distal portion of the adductor femoris to 
reach the popliteal space. This is the space ventrad (or 
caudad) of the knee, between the biceps femoris on one side 
and the semimembranosus on the other. Here the artery 
receives the name A. poplitea, or popliteal artery. The pop- 
liteal artery gives off a number of large branches as it passes 
through the popliteal space, passes between the condyles of 
the femur and underneath the popliteal muscle, and finally 
turns dorsolaterad between the tibia and fibula, just distad of 
the head of the fibula. It now receives the name A. tibialis 
